This invention relates to a magnetic head comprising a control portion to generate a negative pressure, integrally formed on the surface of the magnetic head facing a magnetic disc, thereby achieving a good head touch.
In a recording and reproduction device which uses a thin, flexible magnetic disc as a recording medium, when the magnetic head is simply caused to come in contact against the magnetic disc, the magnetic disc tends to be deformed by the pressure of the magnetic head and to come out of the magnetic head, and stable contact is not obtained.
Heretofore, there has been an attempt in which a stabilizing plate is provided in the vicinity of the magnetic head, which generates a negative pressure in the area where the magnetic head is located, to attract the magnetic disc towards the magnetic head side, thereby achieving a stable contact.
FIG. 17 is a schematic view showing structure of the prior art magnetic disc recording and reproduction device, and FIG. 18 is a schematic perspective view showing part of the device. Referring to these figures, a center core mounted at the center of a magnetic disc 13 is detachably attached to a drive shaft 12 of a drive motor 11 to rotate the magnetic disc 13, and the magnetic disc 13 is rotated at a predetermined rotational speed by the rotation of the drive motor 11.
Below the magnetic disc 13 shown in the figures is disposed a magnetic head 15 which is capable of contacting against the recording surface of the magnetic disc 13 during recording and reproduction operation. The magnetic head 15 is fixed to a carriage 17 engaged with a threaded shaft 16 disposed along the radial direction of the magnetic disc 13 and, by rotating the treaded shaft 16 by a drive unit (not shown), the magnetic head 15 is moved in the radial direction of the magnetic disc 13 to scan the recording surface.
The magnetic head 15 has a head mount 22 fixed to the carriage 17 and a head chip 22 which is fixed to the end of the head mount and has a magnetic gap on a surface opposing the magnetic disc 13, and the magnetic disc 13 comes in sliding contact against the magnetic gap of the head chip to perform recording and reproduction.
Heretofore, the opposing surface having the magnetic gap is formed in a smoothly curved surface protruding towards the magnetic disc 13 side along the rotational direction (arrow R) and the radial direction of the magnetic disc 13 to prevent the recording surface of the magnetic disc 13 from being damaged and to obtain a good head touch.
Furthermore, as shown in FIG. 19, below the magnetic disc 13, a pair of stabilizing plates 19 are provided having inclined surfaces 18 of which one end is located in the vicinity of a free rotary surface N at the upstream side with respect to the rotational direction (arrow R) of the magnetic disc 13 and inclined so as to gradually become more distant from the free rotary surface N towards the downstream side with respect to the rotational direction, with a gap 20 as a moving path of the magnetic head 15.
Thus, the stabilizing plates 19 generate a negative pressure in the area between the magnetic disc 13 and inclined surfaces 18 of the stabilizing plates 19 as the magnetic disc 13 rotates, whereby the negative pressure attracts the magnetic disc 13 towards the magnetic head 15 side to cause the magnetic disc 13 to contact the magnetic gap 24 of the head chip 22 of the magnetic head 15. As a result, in the recording and reproduction operation, the magnetic disc 13 always maintains a stable contact state with the magnetic head 15.
Such negative pressure-generation type stabilizing plates are described in detail, for example, in Japanese Patent Publication Laid-open No. 61-9868/1986, Japanese Patent Publication Laid-open No. 60-219671/1985, Japanese Patent Publication Laid-open No. 62-33380/1987.
In this Specification, the free rotary surface N refers to a rotary surface of the magnetic disc 13 attached to the drive motor 11 of the magnetic disc recording and reproduction device, rotating with no action of external forces other than the rotary driving force.
With the stabilizing plates 19 of a type as shown in FIG. 19, a gap 20 for the magnetic head 15 and the carriage 17 to move the magnetic head is formed between the pair of the stabilizing plates 19. However, since negative pressure is generated by the stabilizing plates 19 mainly in the area between the inclined surfaces 18 formed on the stabilizing plates 19 and the magnetic disc 13, the gap 20 is not concerned in the generation of negative pressure, but rather tends to reduce the negative pressure generated.
Therefore, the above configuration has been defective in that the magnetic disc 13 is attracted towards the inclined surfaces of pair of stabilizing plates 19 located at both sides of the magnetic head 15, but tends to be floated up at the gap 20 where the magnetic head 15 is located, resulting in insufficient contact of the magnetic disc 13 with the magnetic head 15.
Furthermore, since the magnetic head 15 and the stabilizing plates 19 are provided separately, it requires a very complex effort to precisely position the magnetic head 15 and the stabilizing plates 19, which can lead to an increase in cost.